I asked a similar question couple month ago and did not receive any response. What I ended up doing was to "place" it horizontally toward the left front side of the trunk. No drilling or anything, 4 pieces of commercial grade Velcro (just one side) stick directly to the carpet covered trunk board. This is a temporarily solution until I decide on the final location for the sub. However, to date the sub show no sign of movement whatsoever (numerous potholes and aggressive driving). I have not cut out the ski rack hole, but I can hear the sub (though not the "in your face" type of sound), but still better than before. Just don't expect a true custom job quality. If someone else on the board has a better way to secure these, please post. I am going to email Ken at Bvauto about how to secure it. BTW, they mounted bunch of these and claim all location in trunk to sound about equal. You can find in Cardomain a "James" who has the same sub in the trunk mounted vertically. I emailed him to inquire but did not get a reply. Better luck to you and kindly update me if you find out something.

JL